As is known, low-pressure hoses used for connection to diving cylinders for underwater activities are provided by means of an inner tubular element, which is sheathed by a polyester braid, over which there is an outer tubular element, generally made of polyvinyl chloride or polyurethane and designed in practice to create a protective element for the polyester braid, which is mostly entrusted with the function of withstanding the bursting pressure of the hose.
This type of hose, though being used widely for applications in the underwater field, suffers the drawback that, when the hose is bent, the outer sheath, constituted by the PVC or polyurethane hose, tends to separate from the braid, thus forming discontinuities which are particularly damaging, especially when using underwater jackets, in which the hoses are subjected to very tight bending.
The bending of the outer tubular element displaces the filaments of the braid, reducing the strength characteristics of the hose, and infiltrations between the hoses can also occur.
It should be added to the above that the presence of two distinct tubular elements, one superimposed on the other, inevitably leads to an increase in the stiffness of the hose, making it less flexible, and this is particularly disadvantageous, especially when used with underwater jackets in which the hoses are bent considerably.